With a damning report from the public inquiry into the scandal to be published on Wednesday, Dr Heather Wood said Sir David Nicholson was intrinsically linked with the problems at the hospital.

Between 2003 and 2006 Sir David, who is now NHS chief executive, was in charge of the local strategic health authority, which is expected to be blamed for creating the target culture that contributed to patients receiving appalling care.

“He is at the centre of it,” said Dr Wood. “One cannot have confidence in things changing if he is still there.”

Between 400 and 1,200 people died needlessly at Stafford hospital between 2005 and 2009 amid appalling care, with patients left in pain, thirsty and in their own excrement.

Dr Wood, who was investigations manager at the Healthcare Commission, the former health regulator, said the problems were a direct result of the “ruthless implementation of targets regardless of the cost downstream that came from the top, from No10 and from the Department of Health”.

She said there was a “horrific culture” of bullying, with local managers being directly threatened by their superiors that they must meet targets and that ultimately directors of finance were in charge instead of doctors. Dr Wood said Sir David had “an awful lot to answer for”.

A spokesman for Sir David, who this week apologised for the scandal as “a human being and as chief executive”, said he was not prepared to comment.